﻿// PDFsharp - A .NET library for processing PDF
// See the LICENSE file in the solution root for more information.

using System.Text;

namespace PdfSharp.Pdf.Internal
{
    /// <summary>
    /// An encoder for PDF DocEncoding.
    /// </summary>
    sealed class DocEncoding : Encoding
    {
        public DocEncoding()
        { }

        public override int GetByteCount(char[] chars, int index, int count)
        {
            return PdfEncoders.WinAnsiEncoding.GetByteCount(chars, index, count);
        }

        public override int GetBytes(char[] chars, int charIndex, int charCount, byte[] bytes, int byteIndex)
        {
            byte[] ansi = PdfEncoders.WinAnsiEncoding.GetBytes(chars, charIndex, charCount);
            for (int idx = 0, count = ansi.Length; count > 0; idx++, byteIndex++, count--)
                bytes[byteIndex] = AnsiToDoc[ansi[idx]];
            return ansi.Length;
        }

        public override int GetCharCount(byte[] bytes, int index, int count)
        {
            //return PdfEncoders.WinAnsiEncoding.GetCharCount(bytes, index, count);
            Debug.Assert(PdfEncoders.WinAnsiEncoding.GetCharCount(bytes, index, count) == count);
            return count;
        }

        public override int GetChars(byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex)
        {
            PdfDocToUnicode.GetType();
            throw new NotImplementedException("GetChars");
            //for (; byteCount > 0; byteIndex++, charIndex++, byteCount--)
            //  chars[charIndex] = (char)bytes[byteIndex];
            //return byteCount;
        }

        public override int GetMaxByteCount(int charCount)
        {
            return charCount;
        }

        public override int GetMaxCharCount(int byteCount)
        {
            return byteCount;
        }

        /// <summary>
        /// Converts WinAnsi to DocEncode characters. Based upon PDF Reference 1.6.
        /// </summary>
        static readonly byte[] AnsiToDoc = new byte[256]
        {
            //         x0    x1    x2    x3    x4    x5    x6    x7    x8    x9    xa    xb    xc    xd    xe    xf
            /* 00 */ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
            /* 10 */ 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
            /* 20 */ 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
            /* 30 */ 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
            /* 40 */ 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
            /* 50 */ 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
            /* 60 */ 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F,
            /* 70 */ 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F,
            /* 80 */ 0xA0, 0x81, 0x91, 0x83, 0x8C, 0x83, 0x81, 0x82, 0x1A, 0x89, 0x97, 0x88, 0x96, 0x8D, 0x99, 0x8F,
            /* 90 */ 0x90, 0x8F, 0x90, 0x8D, 0x8E, 0x80, 0x85, 0x84, 0x1F, 0x92, 0x90, 0x89, 0x9C, 0x9D, 0x9E, 0x98,
            /* a0 */ 0x20, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF,
            /* b0 */ 0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF,
            /* c0 */ 0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF,
            /* d0 */ 0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
            /* e0 */ 0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF,
            /* f0 */ 0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF,
        };

        // TODO: use this table
        static readonly char[] PdfDocToUnicode = {
            '\x00',   '\x01',   '\x02',   '\x03',   '\x04',   '\x05',   '\x06',   '\x07',   '\x08',   '\x09',   '\x0A',   '\x0B',   '\x0C',   '\x0D',   '\x0E',   '\x0F',
            '\x10',   '\x11',   '\x12',   '\x13',   '\x14',   '\x15',   '\x16',   '\x17',   '\x18',   '\x19',   '\x1A',   '\x1B',   '\x1C',   '\x1D',   '\x1E',   '\x1F',
            '\x20',   '\x21',   '\x22',   '\x23',   '\x24',   '\x25',   '\x26',   '\x27',   '\x28',   '\x29',   '\x2A',   '\x2B',   '\x2C',   '\x2D',   '\x2E',   '\x2F',
            '\x30',   '\x31',   '\x32',   '\x33',   '\x34',   '\x35',   '\x36',   '\x37',   '\x38',   '\x39',   '\x3A',   '\x3B',   '\x3C',   '\x3D',   '\x3E',   '\x3F',
            '\x40',   '\x41',   '\x42',   '\x43',   '\x44',   '\x45',   '\x46',   '\x47',   '\x48',   '\x49',   '\x4A',   '\x4B',   '\x4C',   '\x4D',   '\x4E',   '\x4F',
            '\x50',   '\x51',   '\x52',   '\x53',   '\x54',   '\x55',   '\x56',   '\x57',   '\x58',   '\x59',   '\x5A',   '\x5B',   '\x5C',   '\x5D',   '\x5E',   '\x5F',
            '\x60',   '\x61',   '\x62',   '\x63',   '\x64',   '\x65',   '\x66',   '\x67',   '\x68',   '\x69',   '\x6A',   '\x6B',   '\x6C',   '\x6D',   '\x6E',   '\x6F',
            '\x70',   '\x71',   '\x72',   '\x73',   '\x74',   '\x75',   '\x76',   '\x77',   '\x78',   '\x79',   '\x7A',   '\x7B',   '\x7C',   '\x7D',   '\x7E',   '\x7F',
            '\x2022', '\x2020', '\x2021', '\x2026', '\x2014', '\x2013', '\x0192', '\x2044', '\x2039', '\x203A', '\x2212', '\x2030', '\x201E', '\x201C', '\x201D', '\x2018',
            '\x2019', '\x201A', '\x2122', '\xFB01', '\xFB02', '\x0141', '\x0152', '\x0160', '\x0178', '\x017D', '\x0131', '\x0142', '\x0153', '\x0161', '\x017E', '\xFFFD',
            '\x20AC', '\xA1',   '\xA2',   '\xA3',   '\xA4',   '\xA5',   '\xA6',   '\xA7',   '\xA8',   '\xA9',   '\xAA',   '\xAB',   '\xAC',   '\xAD',   '\xAE',   '\xAF',
            '\xB0',   '\xB1',   '\xB2',   '\xB3',   '\xB4',   '\xB5',   '\xB6',   '\xB7',   '\xB8',   '\xB9',   '\xBA',   '\xBB',   '\xBC',   '\xBD',   '\xBE',   '\xBF',
            '\xC0',   '\xC1',   '\xC2',   '\xC3',   '\xC4',   '\xC5',   '\xC6',   '\xC7',   '\xC8',   '\xC9',   '\xCA',   '\xCB',   '\xCC',   '\xCD',   '\xCE',   '\xCF',
            '\xD0',   '\xD1',   '\xD2',   '\xD3',   '\xD4',   '\xD5',   '\xD6',   '\xD7',   '\xD8',   '\xD9',   '\xDA',   '\xDB',   '\xDC',   '\xDD',   '\xDE',   '\xDF',
            '\xE0',   '\xE1',   '\xE2',   '\xE3',   '\xE4',   '\xE5',   '\xE6',   '\xE7',   '\xE8',   '\xE9',   '\xEA',   '\xEB',   '\xEC',   '\xED',   '\xEE',   '\xEF',
            '\xF0',   '\xF1',   '\xF2',   '\xF3',   '\xF4',   '\xF5',   '\xF6',   '\xF7',   '\xF8',   '\xF9',   '\xFA',   '\xFB',   '\xFC',   '\xFD',   '\xFE',   '\xFF',
        };                                
    }
}
